Liquid crystal layer material, grating device, preparation method and display device

Abstract

The invention discloses a liquid crystal layer material, a grating device, a preparation method and a display device, and relates to the technical field of polarization holographic gratings. The liquid crystal layer material provided by the invention comprises the liquid crystal, the photoinitiator, the chiral agent, the monomer, the resin and the solvent, oxygen inhibition in the UV curing process can be reduced by regulating and controlling the dosage of each component, and the shrinkage phenomenon is reduced by limiting shrinkage during curing. The invention also adjusts the preparation method of the liquid crystal layer, and the boundary conditions of liquid crystal molecules of the liquid crystal layer and an air interface can be destroyed through the release film, the grating device substrate and the like, so that the orientation trend of the liquid crystal layer perpendicular to the surface is reduced, and the liquid crystal layer is more consistent with an expected structure.

Description

Technical Field

[0001] The invention relates to the technical field of polarizer holographic grating, and in particular to a liquid crystal layer material, a grating device and a preparation method thereof, and a display device. Background Art

[0002] Augmented Reality (AR) technology is also known as augmented reality, which can integrate real-world information with virtual-world information. The AR industry has developed rapidly in recent years, and its market share has gradually increased. It is increasingly used in various industries, such as education, training, medical treatment, design, advertising, etc. The core of AR optical display is optical waveguide, which can be realized by diffraction grating. Volume holographic grating is a diffraction grating used for diffraction optical waveguide.

[0003] Polarization Volum Grating (PVG) is a type of volume holographic grating. It has lower haze, excellent diffraction characteristics and a larger FOV than general volume holographic gratings, so it is also suitable for making AR waveguide lenses. AR waveguide lenses are lenses that contain grating structures, and the grating structure will affect the final imaging effect of the waveguide lenses. Since the picture observed by the human eye from the waveguide lens is an image of a region, the perception of the image will involve brightness, brightness uniformity, and contrast.

[0004] The current PVG volume holographic grating will be uneven on the macroscopic level or even produce holes when the liquid crystal layer is solidified due to the contact with the air layer during the preparation process of the liquid crystal layer, which affects the consumer experience. In addition, the liquid crystal molecules at the interface between the liquid crystal layer and the air are restricted by the boundary conditions and have an orientation tendency perpendicular to the surface. Therefore, a section of the structure where the liquid crystal layer and the air interface meet is inconsistent with the liquid crystal orientation at the bottom. The thickness of the liquid crystal layer will affect the upward transmission of the molecular force of the orientation layer. In other words, the arrangement of the liquid crystal is inconsistent with the design value. Therefore, when designing a PVG grating with a higher thickness, it is necessary to expose multiple liquid crystal layers to achieve sufficient thickness in a stacked manner. If multiple liquid crystal layers are exposed, the orientation of the second liquid crystal layer will be affected due to the inconsistent liquid crystal orientation of the interface at the interface between the first liquid crystal layer and the air interface, which will cause deviations in the orientation of the overall liquid crystal layer. In the imaging process, the irregularity of the grating microstructure will affect the imaging in a specific corresponding area.

[0005] Therefore, for the grating in the diffractive optical waveguide lens, there is an urgent need to prepare a grating that is uniform, regular, has no obvious defects in the microstructure, and is closer to the design value.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a liquid crystal layer material, a grating device and a preparation method and a display device, aiming to solve the problem of shrinkage holes occurring during the preparation of a polarizer holographic grating device.

[0008] The present invention is achieved in that:

[0009] In a first aspect, the present invention provides a liquid crystal layer material, which comprises, by mass percentage, 5%-40% liquid crystal, 0.1%-20% photoinitiator, 0.1%-1% chiral agent, 1%-40% monomer, 10%-50% resin and 40%-80% solvent.

[0010] In an optional embodiment, the composition comprises, by mass percentage, 10%-18% liquid crystal, 0.1%-15% photoinitiator, 0.1%-0.6% chiral agent, 2%-4% monomer, 20%-40% resin and 40%-60% solvent.

[0011] In an optional embodiment, the liquid crystal is selected from at least one of DK756, RM257, RM82, BYLC-1, BYLC-2, vinylcyclohexylbenzonitrile, 3,4-difluorophenylbiscyclohexylethylene, methylphenylbiscyclohexylethylene and cyanophenylcyclohexyl-1-propylene;

[0012] and / or, the photoinitiator is selected from at least one of Lucirin TPO, Irgacure 784, Irgacure 184, TPO-L, OXE01, XBPO and QLCURE-BCIM;

[0013] And / or, the chiral agent is selected from R5011, S5011, R811, S811, R6N, S6N, R1011 and CB15.

[0014] In an optional embodiment, the monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, vinyl acetate, isobutyl methacrylate, isobornyl methacrylate, 2-(trifluoromethyl)acrylic acid, hydroxyethyl acrylate, isobornyl acrylate, 2-phenoxyethyl methacrylate, benzyl methacrylate, cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, ethylene glycol dimethacrylate, 4(ethoxy)bisphenol A dimethacrylate, neopentyl glycol diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate;

[0015] and / or, the resin is selected from at least one of AK-80, JW511-1, JW505, JW337-1, JW6211 and JW6144;

[0016] And / or, the solvent is selected from at least one of anhydrous ethanol, ethyl acetate, acetone, toluene, xylene, tetrahydrofuran, n-hexane, propylene glycol methyl ether and propylene glycol methyl ether acetate.

[0017] In a second aspect, the present invention provides a method for preparing a grating device, comprising:

[0018] S11: providing a grating device substrate covered with an alignment layer;

[0019] S12: preparing a first liquid crystal layer on the alignment layer using the liquid crystal layer material in any of the above embodiments;

[0020] S13: After covering the first liquid crystal layer with a release film, solidifying.

[0021] In an optional embodiment, it also includes:

[0022] S14: removing the release film, and preparing a second liquid crystal layer on the first liquid crystal layer using a liquid crystal layer material;

[0023] S15: After covering the second liquid crystal layer with a release film, solidifying;

[0024] S16: Repeat steps S14 and S15 zero or several times until the thickness of the liquid crystal layer reaches the designed value.

[0025] In a third aspect, the present invention provides a method for preparing a grating device, comprising:

[0026] S21: providing a grating device substrate covered with an alignment layer;

[0027] S22: preparing a third liquid crystal layer on the alignment layer using the liquid crystal layer material in any of the above embodiments;

[0028] S23: Under vacuum, the surface of the third liquid crystal layer is covered with a grating device substrate and solidified.

[0029] Preferably, the preparation method further comprises:

[0030] S25: The grating device substrate close to the surface of the third liquid crystal layer is coated with a release agent, the grating device substrate is removed, and a fourth liquid crystal layer is prepared on the third liquid crystal layer using a liquid crystal layer material;

[0031] S26: Under vacuum, the surface of the fourth liquid crystal layer is covered with a grating device substrate and solidified;

[0032] S27: Repeat steps S25 and S26 zero or several times until the thickness of the liquid crystal layer reaches the designed value.

[0033] In an optional embodiment, the curing step includes: breaking the vacuum state of the third liquid crystal layer or the fourth liquid crystal layer covering the surface, and curing under normal pressure.

[0034] In a fourth aspect, the present invention provides a grating device prepared by any one of the preparation methods in the aforementioned embodiments.

[0035] In a fifth aspect, the present invention provides a display device, comprising the grating device of the aforementioned embodiment.

[0036] The present invention has the following beneficial effects: the liquid crystal layer material provided by the present invention includes liquid crystal, photoinitiator, chiral agent, monomer, resin and solvent. By adjusting the amount of each component, oxygen inhibition during UV curing can be reduced, and the shrinkage during curing can be limited to reduce the occurrence of shrinkage cavitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 is a schematic diagram after the alignment layer is formed;

[0039] Figure 2 is a schematic diagram after the alignment layer and the liquid crystal layer are formed;

[0040] Figure 3 It is a schematic diagram after forming an alignment layer, a first liquid crystal layer, and a second liquid crystal layer;

[0041] Figure 4 It is a liquid crystal orientation diagram of the orientation layer and the first liquid crystal layer; a single shape in the diagram represents the orientation of the liquid crystal;

[0042] Figure 5 for Figure 4 Interface change diagram of the first liquid crystal layer near the air layer;

[0043] Figure 6 Schematic diagram of forming a liquid crystal layer using a grating device substrate.

[0044] Icon: 101-substrate; 102-orientation layer; 201-substrate; 202-orientation layer; 203-liquid crystal layer; 301-substrate; 302-orientation layer; 303-first liquid crystal layer; 304-second liquid crystal layer; 401-orientation layer; 402-first liquid crystal layer; 501-orientation layer; 502-first liquid crystal layer; 503-interface close to the air layer in the first liquid crystal layer; 601-substrate; 602-orientation layer; 603-liquid crystal layer; 604-grating device substrate. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0046] The embodiment of the present invention provides a liquid crystal layer material, which includes 5%-40% of liquid crystal, 0.1%-20% of photoinitiator, 0.1%-1% of chiral agent, 1%-40% of monomer, 10%-50% of resin and 40%-80% of solvent by mass percentage. By introducing chiral agent, monomer and resin, and adjusting the amount of each component, oxygen inhibition in the UV curing process can be reduced, and shrinkage can be reduced by limiting shrinkage during curing.

[0047] Specifically, in terms of mass percentage, the mass fraction of the liquid crystal can be 5%, 10%, 15%, 18%, 20%, 25%, 30%, 35%, 40%, etc.; the mass fraction of the photoinitiator can be 0.1%, 0.5%, 1.0%, 5.0%, 10.0%, 15.0%, 20.0%, etc.; the mass fraction of the chiral agent can be 0.1%, 0.3%, 0.5%, 0.6%, 0.8%, 1.0%. etc.; the mass fraction of the monomer can be 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% etc.; the mass fraction of the resin can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% etc.; the mass fraction of the solvent can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% etc.

[0048] In a preferred embodiment, by mass percentage, the composition includes 10%-18% liquid crystal, 0.1%-15% photoinitiator, 0.1%-0.6% chiral agent, 2%-4% monomer, 20%-40% resin and 40%-60% solvent. By further optimizing the dosage of each component, the shrinkage during curing can be further limited and the occurrence of shrinkage cavity can be reduced.

[0049] In some embodiments, the liquid crystal is selected from at least one of DK756, RM257, RM82, BYLC-1, BYLC-2, vinylcyclohexylbenzonitrile, 3,4-difluorophenylbiscyclohexylethylene, methylphenylbiscyclohexylethylene and cyanophenylcyclohexyl-1-propylene, and the liquid crystal component can be any one or more of the above. Specifically, DK756, RM257, RM82, BYLC-1, BYLC-2 all represent trade names, such as DK756, whose main component is 2,5-bis-O-[4-[[4-[[[4-(acryloyloxy)butoxy]carbonyl]oxy]benzoyl]oxy]benzoyl]-1,4:3,6-dianhydride-D-glucitol, which can be purchased from Guangdong Yunxing Biotechnology Co., Ltd.; RM257, whose main component is 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene, can be purchased from Beijing Solaibaoke Technology Co., Ltd.; the main component of RM82 is 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene, which can be purchased from Jinan Tengyuan Chemical Technology Co., Ltd.; the main component of BYLC-1 is 2,5-bis[4-(acryloyloxy)benzoyl]isosorbide anhydride, which can be purchased from Beijing Bayi Space-Time Liquid Crystal Technology Co., Ltd.; the main component of BYLC-2 is 2-methyl-1,4-phenylene bis(4-(4-(acryloyloxy)butoxy)benzoate), which can be purchased from Beijing Bayi Space-Time Liquid Crystal Technology Co., Ltd.

[0050] In some embodiments, the photoinitiator is selected from at least one of Lucirin TPO, Irgacure 784, Irgacure 184, TPO-L, OXE01, XBPO and QLCURE-BCIM. The photoinitiator can be any one or more of the above, and all of them can initiate monomer polymerization under ultraviolet light. Specifically, the main component of Lucirin TPO is diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, which can be purchased from Wuhan Kemik Biomedical Technology Co., Ltd.; the main component of Irgacure 784 is bis (2,6-difluoro-3-pyrrolophenyl) titanocene, which can be purchased from Tianjin CITIC Kaitai Chemical Co., Ltd.; the main component of Irgacure 184 is 1-hydroxycyclohexyl phenyl ketone, which can be purchased from Zhejiang Shouerfu Chemical Trading Co., Ltd.; the main component of TPO-L is ethyl 2,4,6-trimethylbenzoylphenylphosphonate, which can be purchased from Wuhan Xingzhongcheng Technology Co., Ltd.; the main component of OXE01 is 2-((benzoyloxy)imino)-1-(4-(phenylthio)phenyl)octan-1-one, which can be purchased from BASF SE; the main component of QLCURE-BCIM is 1,2'-bis(2-chlorophenyl)-tetraphenylbiimidazole, which can be purchased from Wuhan Jixinyibang Biotechnology Co., Ltd.

[0051] In some embodiments, the chiral agent is selected from R5011, S5011, R811, S811, R6N, S6N, R1011 and CB15. The chiral agent can be any one or more of the above, and all of them can control the stereoselectivity during the polymerization of the monomer to obtain a uniform liquid crystal layer. The above chiral agents are all commercially available raw materials, and the above abbreviations are usually used to represent the chiral agent, and their specific components are not described in detail.

[0052] In some embodiments, the monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, vinyl acetate, isobutyl methacrylate, isobornyl methacrylate, 2-(trifluoromethyl)acrylic acid, hydroxyethyl acrylate, isobornyl acrylate, 2-phenoxyethyl methacrylate, benzyl methacrylate, cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate (n=13), polyethylene glycol diacrylate (n=9), polyethylene glycol diacrylate (n=5), tripropylene glycol diacrylate, ethylene glycol dimethacrylate, 4(ethoxy)bisphenol A dimethacrylate, neopentyl glycol diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate. The type of the monomer may be any one or more of the above, and all of them can form a uniform liquid crystal layer after polymerization.

[0053] In some embodiments, the resin is selected from at least one of AK-80, JW511-1, JW505, JW337-1, JW6211 and JW6144. The resin can be any one or more of the above. The addition of the resin can introduce multi-functional components, increase the reaction rate, and thus improve oxygen inhibition. In addition, the introduction of the long-chain macromolecular structure of the resin can also reduce the curing shrinkage during the UV process, thereby improving the flatness at the microscopic level. The main component of AK-80 is difunctional acrylic resin, which can be purchased from Guangzhou Jiuwei Trading Co., Ltd.; the main component of JW511-1 is multifunctional resin, which can be purchased from Zhongshan Jingwei New Materials Co., Ltd.; the main component of JW505 is multifunctional resin, which can be purchased from Zhongshan Jingwei New Materials Co., Ltd.; the main component of JW337-1 is trifunctional acrylic resin, which can be purchased from Zhongshan Jingwei New Materials Co., Ltd.; the main component of JW6211 is multifunctional polyurethane resin, which can be purchased from Zhongshan Jingwei New Materials Co., Ltd.; the main component of JW6144 is multifunctional polyurethane resin, which can be purchased from Zhongshan Jingwei New Materials Co., Ltd.

[0054] In some embodiments, the solvent is selected from at least one of anhydrous ethanol, ethyl acetate, acetone, toluene, xylene, tetrahydrofuran, n-hexane, propylene glycol methyl ether and propylene glycol methyl ether acetate. The solvent can be any one or more of the above, all of which can disperse the components well to form a uniform liquid crystal layer.

[0055] The embodiment of the present invention provides a method for preparing a grating device, and a liquid crystal layer is prepared using the liquid crystal layer material provided by the embodiment of the present invention. In the actual operation process: firstly, a grating device substrate covered with an alignment layer is provided, and then a liquid crystal layer is prepared.

[0056] like Figure 1 and Figure 2 As shown, an alignment layer 102 is prepared on a substrate 101 , and then a liquid crystal layer 203 is prepared on the exposed alignment layer 202 .

[0057] In some embodiments, at least two liquid crystal layers may be formed by multi-layer curing to meet the thickness requirement.

[0058] like Figure 3 As shown, after the alignment layer 302 is formed on the substrate 301, the first liquid crystal layer 303 is formed first, and then the second liquid crystal layer 304 is formed on the first liquid crystal layer 303, and so on, and the designed thickness is achieved through multi-layer curing. Specifically, the liquid crystal layer material provided by the embodiment of the present invention is dispersed on the exposed alignment layer 302, and then UV curing is performed to form the first liquid crystal layer 303; the liquid crystal layer material is further dispersed on the cured first liquid crystal layer 303, and then UV curing is performed to form the second liquid crystal layer 304, and so on, the designed thickness is achieved through multi-layer curing.

[0059] Specifically, before dispersion, the liquid crystal layer material can be ultrasonically treated at 40°C-60°C for 10min-60min to achieve a uniform dispersion effect, and the ultrasonically treated liquid crystal layer material is dispersed on the exposed orientation layer, and the dispersion method can be spin coating, printing or spraying. After uniform dispersion, it is placed under a 365nm LED lamp for UV curing to finally obtain the first liquid crystal layer 303. According to the designed thickness requirements, on the cured first liquid crystal layer 303, the liquid crystal layer material can continue to be dispersed in the above manner, and placed under a 365nm LED lamp for UV curing again as the second liquid crystal layer. By analogy, multi-layer curing can be performed to achieve different designed thicknesses.

[0060] It should be noted that if Figure 4 As shown, the structure formed includes an alignment layer 401 and a first liquid crystal layer 402. The microstructure of the first liquid crystal layer 402 is as shown in FIG. Figure 4 The first liquid crystal layer produced according to the method of the above embodiment has a liquid crystal orientation at the interface with air that is restricted by boundary conditions and has an orientation tendency perpendicular to the surface. The actual microstructure is as follows: Figure 5 (including the alignment layer 501, the first liquid crystal layer 502, and the interface 503 in the first liquid crystal layer close to the air layer). Figure 5In the embodiment, the arrangement of several layers of liquid crystal molecules at the interface 503 of the upper first liquid crystal layer close to the air layer is inconsistent with the arrangement in the alignment layer 401, and there will be some deviation from the design. If the traditional liquid crystal layer formula is used, it will cause surface unevenness or even holes during the UV curing process due to oxygen inhibition and UV curing shrinkage due to direct contact with air.

[0061] Furthermore, if you press Figure 5 The liquid crystal orientation of the second liquid crystal layer prepared by the method of the embodiment of the present invention depends on the liquid crystal orientation of the interface between the first liquid crystal layer and the second liquid crystal layer. Since the liquid crystal orientation above the first liquid crystal layer is not as expected and the second liquid crystal layer does not have a good structure, the grating structure of the second liquid crystal layer is affected, and further the effect of the grating is affected.

[0062] In order to improve the above problems, the preparation of the orientation layer and the polarization holographic exposure are maintained unchanged, and the preparation method of the PVG volume holographic grating device is adjusted, among which the preparation steps of the liquid crystal layer are adjusted in particular. According to the different preparation methods of the liquid crystal layer, it can be divided into the following two methods:

[0063] Method 1: Use release film

[0064] The main steps are as follows:

[0065] S11: providing a grating device substrate covered with an alignment layer;

[0066] like Figure 1 As shown, an alignment layer 102 is prepared on a substrate 101 . The preparation process of the alignment layer 102 is not limited, and the existing preparation process of the alignment layer can be adopted. After the alignment layer 102 is prepared, polarization holographic exposure is performed.

[0067] In some embodiments, the substrate is selected from at least one of glass and hard plastic sheet. The substrate can be any one or more of the above, and can be selected according to the performance requirements of the product.

[0068] In some embodiments, the process of preparing the alignment layer includes: dispersing a brilliant yellow solution (hereinafter referred to as BY solution) with a mass fraction of 0.5%-2% on the substrate, and then baking to obtain an alignment layer with a thickness of 10nm-20nm. Specifically, BY represents brilliant yellow, the solvent of the BY solution can be DMF (N, N-dimethylformamide), the mass fraction of the BY solution can be 0.5%, 1.0%, 1.5%, 2.0%, etc., and the thickness of the alignment layer formed after baking can be 10nm, 13nm, 15nm, 18nm, 20nm, etc. by adjusting the coating amount of the BY solution.

[0069] There is no limit to the method of dispersing the BY solution, which may be by spin coating, printing, spraying, etc. There is no limit to the operating parameters during baking, such as the baking temperature may be controlled to be 100°C-150°C, and the baking time may be controlled to be 0.5h-3h.

[0070] In some embodiments, the polarization holographic exposure method is not limited, for example, the material of the alignment layer may be deflected in the direction of the interference light by interference of two coherent circularly polarized lights.

[0071] S12: preparing a first liquid crystal layer on the alignment layer using a liquid crystal layer material;

[0072] After the alignment layer 202 is formed on the substrate 201 , a first liquid crystal layer is prepared on the exposed alignment layer 202 using a liquid crystal layer material.

[0073] S13: After covering the release film on the first liquid crystal layer, solidifying;

[0074] After the liquid crystal layer material is dispersed on the exposed alignment layer, a release film is rolled on the surface of the liquid crystal layer material, and then UV curing is performed.

[0075] If two or more layers need to be prepared, the following steps are also included:

[0076] S14: removing the release film, and preparing a second liquid crystal layer on the first liquid crystal layer using a liquid crystal layer material;

[0077] S15: After covering the second liquid crystal layer with a release film, solidifying;

[0078] S16: Repeat steps S14 and S15 zero or several times until the thickness of the liquid crystal layer reaches the designed value.

[0079] Specifically, the release film is torn off on the cured first liquid crystal layer; the liquid crystal layer material is dispersed on the first liquid crystal layer, a release film is rolled on the surface of the liquid crystal layer material, and then UV curing is performed to form a second liquid crystal layer, and the release film is torn off on the cured second liquid crystal layer; and so on, the designed thickness is achieved through multi-layer curing, such as Figure 3 The provision of the release film can destroy the boundary conditions of the liquid crystal molecules at the interface between the liquid crystal layer and the air, thereby reducing their orientation tendency perpendicular to the surface and making them more consistent with the expected structure.

[0080] Specifically, after the liquid crystal layer material is evenly dispersed on the exposed alignment layer, a release film is rolled on the surface of the liquid crystal layer material with a silicone soft roller, and then placed under a 365nm LED lamp for UV curing to finally obtain the first liquid crystal layer. According to the designed thickness, the release film is torn off on the cured first liquid crystal layer, and then the second liquid crystal layer is prepared according to the above method. Multiple layers of curing can be performed in this way to achieve different designed thicknesses.

[0081] Method 2: Using grating device substrate

[0082] The main steps are as follows:

[0083] S21: providing a grating device substrate covered with an alignment layer;

[0084] Please refer to S11 for the specific content, which will not be repeated here.

[0085] S22: preparing a third liquid crystal layer on the alignment layer using a liquid crystal layer material;

[0086] The liquid crystal layer material is evenly dispersed on the exposed alignment layer to prepare the third liquid crystal layer.

[0087] S23: Under vacuum, the surface of the third liquid crystal layer is covered with a grating device substrate and solidified;

[0088] Will be like Figure 2 The overall structure shown is placed in a vacuum chamber. Figure 2 Above the structure, a suction cup is used to hold the grating device substrate. After vacuuming, the suction cup releases the grating device substrate, allowing the grating device substrate to fall down to contact the liquid crystal layer. Finally, the vacuum is broken, the structure is taken out, UV curing is performed under normal pressure, and then the grating device substrate is removed to form the third liquid crystal layer.

[0089] like Figure 6 As shown, it includes a substrate 601, an orientation layer 602, a liquid crystal layer 603, and a grating device substrate 604. The grating device substrate 604 can destroy the boundary conditions of the liquid crystal molecules at the interface between the liquid crystal layer and the air, thereby reducing their orientation tendency perpendicular to the surface, making it more consistent with the expected structure.

[0090] Specifically, in the Figure 2 After the cavity of the structure is evacuated to 1Pa, the suction cup releases the grating device substrate 604, and the grating device substrate 604 falls and contacts the liquid crystal layer material. Finally, the vacuum is broken, the structure is taken out, and then placed under a 365nm LED lamp for normal pressure UV curing, and finally the third liquid crystal layer (such as Figure 6 ).

[0091] If two or more layers need to be prepared, the following steps are also included:

[0092] S25: The grating device substrate close to the surface of the third liquid crystal layer is coated with a release agent, the grating device substrate is removed, and a fourth liquid crystal layer is prepared on the third liquid crystal layer using a liquid crystal layer material;

[0093] S26: Under vacuum, the surface of the fourth liquid crystal layer is covered with a grating device substrate and solidified;

[0094] S27: Repeat steps S25 and S26 zero or several times until the thickness of the liquid crystal layer reaches the designed value, and perform multi-layer curing in this way to achieve different designed thicknesses.

[0095] In some embodiments, the side of the grating device substrate 604 that contacts the liquid crystal layer is coated with a release agent. After UV curing, the grating device substrate 604 can be lifted by hand or with corresponding equipment; the fourth liquid crystal layer is prepared on the third liquid crystal layer using the liquid crystal layer material, and the grating device substrate is covered on the surface of the fourth liquid crystal layer under vacuum and cured. During curing, it is also necessary to break the vacuum state of the fourth liquid crystal layer and cure under normal pressure. By analogy, the steps of coating, covering the grating device substrate, curing, and removing the grating device substrate are repeated to perform multi-layer curing.

[0096] An embodiment of the present invention provides a grating device, which is prepared by the preparation method provided by the embodiment of the present invention. By destroying the boundary conditions of the liquid crystal molecules at the interface between the liquid crystal layer and the air, the orientation trend of the liquid crystal molecules perpendicular to the surface is reduced, making them more consistent with the expected structure, which is beneficial to improving the grating effect.

[0097] An embodiment of the present invention further provides a display device, including the above-mentioned grating device. By improving the performance of the grating device, the display effect of the display device is improved.

[0098] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0099] Example 1

[0100] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, 15% RM257, 8% TPO-L, 0.1% R5011, 0.1% S5011, 1% isobornyl methacrylate, 3% polyethylene glycol diacrylate (n=5, n represents the degree of polymerization), 30% JW511-1 and 42.8% ethyl acetate.

[0101] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0102] This embodiment provides a method for preparing a grating device, the steps are as follows:

[0103] (1) Preparation of Orientation Layer

[0104] First, a layer of 1wt% BY solution (brilliant yellow, solvent is N,N-dimethylformamide) is dispersed on a clean substrate (glass substrate with a thickness of 400μm), and the dispersion method can be spin coating. After uniform dispersion, it is placed in an oven and baked at 130℃ for 1h to finally obtain an alignment layer of about 15nm.

[0105] (Right now Figure 1 structure).

[0106] (2) Polarization holographic exposure

[0107] A laser with a wavelength of 457nm is used to split left-handed and right-handed circularly polarized light beams, and the two beams are made equal in intensity. At this time, the two beams are coherent and interfere with each other, and the polarization state changes periodically in space, causing the material of the alignment layer to deflect in the direction of the interference light. The exposure angle is selected to be 30°.

[0108] (3) Preparation of Liquid Crystal Layer

[0109] The PVG volume holographic liquid crystal layer material provided in this embodiment is ultrasonicated at 50°C for 30 minutes, and then the ultrasonicated PVG volume holographic liquid crystal layer material is dispersed on the exposed alignment layer by spin coating. After being evenly dispersed, it is placed under a 365nm LED lamp for UV curing for 3 minutes to finally obtain the first liquid crystal layer.

[0110] According to the designed thickness, the PVG volume holographic liquid crystal layer material can be dispersed in the above manner on the cured first liquid crystal layer, and then placed under a 365nm LED lamp for UV curing to form the second liquid crystal layer. In this way, multiple layers of curing can be performed to achieve different designed thicknesses (the total thickness of the liquid crystal layer is 100nm, and the number of curing times is 4 times in total).

[0111] Example 2

[0112] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, 18% BYLC-1, 15% Irgacure184, 0.2% CB15, 0.2% R1011, 2% hydroxyethyl acrylate, 20% JW6144 and 44.6% toluene.

[0113] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0114] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0115] Example 3

[0116] The present embodiment provides a liquid crystal layer material, which includes, by mass percentage, 12% BYLC-2, 6% TPO-L, 0.15% R811, 0.15% S811, 1% n-butyl methacrylate, 1% trimethylolpropane triacrylate, 20% AK-80 and 59.7% toluene.

[0117] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0118] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0119] Example 4

[0120] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, 10% RM257, 45% Irgacure 78, 0.1% R6N, 0.1% S6N, 3% vinyl acetate, 40% JW337-1 and 41.8% ethyl acetate.

[0121] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0122] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0123] Example 5

[0124] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, RM82 11%, Lucirin TPO 6%, R5011 0.3%, S5011 0.3%, ethylene glycol dimethacrylate 2%, JW505 25% and ethyl acetate 55.4%.

[0125] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0126] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0127] Example 6

[0128] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, 15% RM257, 8% TPO-L, 0.1% R5011, 0.1% S5011, 1% isobornyl methacrylate, 3% polyethylene glycol diacrylate (n=5, n represents the degree of polymerization), 30% AK-80 and 42.8% ethyl acetate.

[0129] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0130] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0131] Example 7

[0132] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, 15% RM257, 8% TPO-L, 0.1% R5011, 0.1% S5011, 1% isobornyl methacrylate, 3% polyethylene glycol diacrylate (n=5, n represents the degree of polymerization), 30% JW337-1 and 42.8% ethyl acetate.

[0133] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0134] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0135] Example 8

[0136] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, 15% RM257, 8% TPO-L, 0.1% R5011, 0.1% S5011, 1% isobornyl methacrylate, 3% polyethylene glycol diacrylate (n=5, n represents the degree of polymerization), 30% JW6211 and 42.8% ethyl acetate.

[0137] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0138] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0139] Example 9

[0140] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, RM82 5%, Lucirin TPO 20%, R5011 0.5%, S5011 0.5%, ethylene glycol dimethacrylate 15%, JW505 15% and ethyl acetate 44%.

[0141] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0142] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0143] Example 10

[0144] This embodiment provides a liquid crystal layer material, which includes, by mass percentage, 15.8% of RM82, 0.1% of Lucirin TPO, 0.05% of R5011, 0.05% of S5011, 1% of ethylene glycol dimethacrylate, 43% of JW505, and 40% of ethyl acetate.

[0145] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0146] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The specific steps refer to Embodiment 1.

[0147] Embodiment 11

[0148] This embodiment provides a liquid crystal layer material, and the composition and preparation method refer to those of Embodiment 1.

[0149] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The steps are as follows:

[0150] (1) Preparation of Orientation Layer

[0151] Refer to Example 1.

[0152] (2) Polarization holographic exposure

[0153] Refer to Example 1.

[0154] (3) Preparation of Liquid Crystal Layer

[0155] The liquid crystal layer material prepared in this embodiment is ultrasonicated at 50°C for 30 minutes, and then the ultrasonicated liquid crystal layer material is dispersed on the exposed alignment layer by spin coating. After uniform dispersion, a release film is rolled on the surface of the liquid crystal layer material with a silicone soft roller. Then, it is placed under a 365nm LED lamp for UV curing (curing time is the same as in Example 1), and finally the first liquid crystal layer is obtained.

[0156] According to the designed thickness, on the cured first liquid crystal layer, the release film is torn off, and then the second liquid crystal layer is prepared in the above manner. Multiple layers of curing can be performed in this way to achieve different designed thicknesses. (The total thickness of the liquid crystal layer and the number of curing times are consistent with those in Example 1).

[0157] Example 12

[0158] This embodiment provides a liquid crystal layer material, and the composition and preparation method refer to those of Embodiment 1.

[0159] This embodiment provides a method for preparing a grating device. The liquid crystal layer material of this embodiment is used to prepare a liquid crystal layer. The steps are as follows:

[0160] (1) Preparation of Orientation Layer

[0161] Refer to Example 1.

[0162] (2) Polarization holographic exposure

[0163] Refer to Example 1.

[0164] (3) Preparation of Liquid Crystal Layer

[0165] The liquid crystal layer material prepared in this embodiment is ultrasonicated at 50°C for 30 minutes, and then the ultrasonicated liquid crystal layer material is dispersed on the exposed alignment layer by spin coating. Figure 2 The whole structure is placed in a vacuum chamber. Figure 2 Above the structure, there is a grating device substrate 604 sucked by a suction cup. The grating device substrate 604 can be glass. The plane of the grating device substrate 604 in contact with the liquid crystal layer is coated with a release agent (CN-1156, modified silicone oil, Guangdong Zhongke Hongtai New Materials Co., Ltd.). Figure 2 After the cavity of the structure is evacuated to 1Pa, the suction cup releases the grating device substrate 604, and the grating device substrate 604 falls and contacts the liquid crystal layer material. Finally, the vacuum is broken and the structure is taken out. Then it is placed under a 365nm LED light for UV curing, and finally the first liquid crystal layer (such as Figure 6 After UV curing, lift the grating device substrate 604 by hand or with a corresponding device, and then prepare the second liquid crystal layer according to the above steps. In this way, multi-layer curing can be performed to achieve different designed thicknesses (the total thickness of the liquid crystal layer and the number of curing times are consistent with those in Example 1).

[0166] Comparative Example 1

[0167] This comparative example provides a liquid crystal layer material, which comprises, by mass percentage, 18% BYLC-1, 15% Irgacure184, 0.2% CB15, 0.2% R1011, 2% hydroxyethyl acrylate and 64.6% toluene.

[0168] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0169] This comparative example provides a method for preparing a grating device, and the liquid crystal layer is prepared by using the liquid crystal layer material of this embodiment. The specific steps refer to Example 1.

[0170] Note: The only difference between Comparative Example 1 and Example 2 is that the JW6144 resin is replaced with an equal amount of toluene solvent.

[0171] Comparative Example 2

[0172] This comparative example provides a liquid crystal layer material, which includes, by mass percentage, 8% TPO-L, 0.1% R5011, 0.1% S5011, 1% isobornyl methacrylate, 3% polyethylene glycol diacrylate (n=5), 30% JW511-1 and 57.8% ethyl acetate.

[0173] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0174] This comparative example provides a method for preparing a grating device, and the liquid crystal layer is prepared by using the liquid crystal layer material of this embodiment. The specific steps refer to Example 1.

[0175] Note: The only difference between Comparative Example 2 and Example 1 is that RM257 is replaced by an equal amount of ethyl acetate solvent.

[0176] Comparative Example 3

[0177] This comparative example provides a liquid crystal layer material, which comprises, by mass percentage, 10% of RM257, 5% of Irgacure784, 0.1% of R6N, 0.1% of S6N, 3% of vinyl acetate and 81.8% of ethyl acetate.

[0178] Weigh the raw materials of each component according to the above mass ratio, put them into ultrasonic dispersing equipment, and perform ultrasonic dispersing at a temperature of 50° C. for 30 minutes to disperse them uniformly, thereby obtaining a PVG volume holographic liquid crystal layer material.

[0179] This comparative example provides a method for preparing a grating device, and the liquid crystal layer is prepared by using the liquid crystal layer material of this embodiment. The specific steps refer to Example 1.

[0180] Note: The only difference between Comparative Example 3 and Example 4 is that the JW337-1 resin is replaced with an equal amount of ethyl acetate solvent.

[0181] Test Example 1

[0182] The grating devices prepared in the examples and comparative examples were visually inspected, and the results are shown in Table 1.

[0183] Table 1 Test results of grating devices prepared in Examples and Comparative Examples

[0184]

[0185]

[0186] It can be seen from Table 1 that the liquid crystal layer material provided by the embodiment of the present invention can effectively avoid the shrinkage problem.

[0187] By comparing Example 1 with Examples 11-12, it can be seen that the preparation methods of Examples 11 and 12 can further improve the brightness of the product compared with Example 1.

[0188] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A liquid crystal layer material, characterized in that: Calculated by mass percentage, it includes 5%-40% of liquid crystal, 0.1%-20% of photoinitiator, 0.1%-1% of chiral agent, 1%-40% of monomer, 10%-50% of resin and 40%-80% of solvent.

2. The liquid crystal layer material according to claim 1, characterized in that: Calculated by mass percentage, it includes 10%-18% of liquid crystal, 0.1%-15% of photoinitiator, 0.1%-0.6% of chiral agent, 2%-4% of monomer, 20%-40% of resin and 40%-60% of solvent.

3. The liquid crystal layer material according to claim 1 or 2, characterized in that: The liquid crystal is selected from at least one of DK756, RM257, RM82, BYLC-1, BYLC-2, vinylcyclohexylbenzonitrile, 3,4-difluorophenylbiscyclohexylethylene, methylphenylbiscyclohexylethylene and cyanophenylcyclohexyl-1-propylene; and / or, the photoinitiator is selected from at least one of Lucirin TPO, Irgacure 784, Irgacure 184, TPO-L, OXE01, XBPO and QLCURE-BCIM; And / or, the chiral agent is selected from R5011, S5011, R811, S811, R6N, S6N, R1011 and CB15.

4. The liquid crystal layer material according to claim 1 or 2, characterized in that: The monomer is selected from at least one of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, vinyl acetate, isobutyl methacrylate, isobornyl methacrylate, 2-(trifluoromethyl)acrylic acid, hydroxyethyl acrylate, isobornyl acrylate, 2-phenoxyethyl methacrylate, benzyl methacrylate, cyclohexanedimethanol diacrylate, polyethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, ethylene glycol dimethacrylate, 4(ethoxy)bisphenol A dimethacrylate, neopentyl glycol diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate; and / or, the resin is selected from at least one of AK-80, JW511-1, JW505, JW337-1, JW6211 and JW6144; And / or, the solvent is at least one selected from anhydrous ethanol, ethyl acetate, acetone, toluene, xylene, tetrahydrofuran, n-hexane, propylene glycol methyl ether and propylene glycol methyl ether acetate.

5. A method for preparing a grating device, characterized in that: include: S11: providing a grating device substrate covered with an alignment layer; S12: preparing a first liquid crystal layer on the alignment layer using the liquid crystal layer material according to any one of claims 1 to 4; S13: After covering the first liquid crystal layer with a release film, solidifying it.

6. The preparation method according to claim 5, characterized in that: Also includes: S14: removing the release film, and preparing a second liquid crystal layer on the first liquid crystal layer using the liquid crystal layer material; S15: Covering the second liquid crystal layer with a release film and then curing the layer; S16: Repeat steps S14 and S15 zero or several times until the thickness of the liquid crystal layer reaches the designed value.

7. A method for preparing a grating device, characterized in that: include: S21: providing a grating device substrate covered with an alignment layer; S22: preparing a third liquid crystal layer on the alignment layer using the liquid crystal layer material according to any one of claims 1 to 4; S23: Under vacuum, covering the surface of the third liquid crystal layer with a grating device substrate and solidifying; Preferably, the preparation method further comprises: S25: the grating device substrate close to the surface of the third liquid crystal layer is coated with a release agent, the grating device substrate is removed, and a fourth liquid crystal layer is prepared on the third liquid crystal layer using the liquid crystal layer material; S26: Under vacuum, covering the surface of the fourth liquid crystal layer with a grating device substrate and solidifying; S27: Repeat steps S25 and S26 zero or several times until the thickness of the liquid crystal layer reaches the designed value.

8. The preparation method according to claim 7, characterized in that: It is characterized in that The curing step comprises: The vacuum state of the third liquid crystal layer or the fourth liquid crystal layer covering the surface is broken, and the liquid crystal is cured under normal pressure.

9. A grating device, characterized in that: It is prepared by the preparation method described in any one of claims 5 to 8.

10. A display device, characterized in that: Comprising the grating device as claimed in claim 9.

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